The present invention relates to a temperature control system for printing press cylinders and particularly to a system for blowing cooling air and recirculating the cooling air.
The invention is particularly suitable for offset printing presses. The cylinders of printing presses heat up during operation and they can be cooled by air which is blown onto the outer surfaces of the cylinders. The air is cooled to a desired temperature in a cold air generator by a heat exchanger. If the cooled air is warmer than the cylinders of the press when the press starts operation, the air effects a faster heating of these printing press cylinders to the desired operating temperature. After the operating temperature has been reached, if the temperature of the printing press cylinders increases further, the air cools the printing press cylinders. Printing cylinders which are to be heated or cooled are, in particular, printing plate cylinders, rubber-blanket cylinders, impression cylinders, and inking rolls which transfer the printing ink from a source of ink to the printing plate cylinder. Good qualities of print are obtained when a printing plate cylinder has a temperature of between 24.degree. and 27.degree. C.
Comparable temperature control systems are known from Japanese Patent Application Publications Nos. 56-127457 and 1-72846; EPO 480 230 A1, U.S. Pat. No. 1,749,316, GB 1 534 340, German OS 19 53 590 and German OS 35 41 458 A1.